In the market today, there are offered many different types of digital apparatus, such as for example cell phones, mobile telephones, digital personal organizers, personal data assistants (PDAs) and smartphones. Usually, these digital apparatus has either a mechanical keyboard and a display screen or a touch screen display incorporating a touch keyboard. An example of a digital apparatus, more specific a smartphone, is illustrated in FIG. 1, wherein the smartphone is generally indicated by 10. The smartphone 10 includes a display screen 20, for example implemented using liquid crystal display (LCD) or Light Emitting Diode (LED) technology, for displaying information such as text and images to a user of the smartphone 10. Moreover, the smartphone display screen 20 further displays a touch keyboard 30 for inputting data into the smartphone 10, for example numerical data for dialing and text for writing special messaging service (SMS), emails and documents in text editor application programs. Furthermore, as shown in FIG. 2 other component parts of the smartphone include a microphone 40 and a loudspeaker 50 coupled to a data processor 60. Moreover, the smartphone 10 also includes an antenna 70 coupled to radio frequency circuits 80 coupled in turn to the data processor 60 of the smartphone 10 for enabling said smartphone 10 to communicate by wireless to a mobile telephone network (not shown); such communication to the mobile telephone network is implemented at a radio communication frequency in an order of 1 GHz. Optionally, the smartphone 10 is also capable of communicating directly, via a wireless interface 90 coupled to the data processor 60, with other devices in close spatial proximity to the telephone 10, by WiFi, Bluetooth, Radio Frequency Identification Devices (RFID), Near field communication (NFC) or similar protocols. Such other devices include, for example, an earphone, a headset microphone, a keyboard or a computer pointing device.
Digital apparatus, such as smartphones, are becoming progressively more complex with time as manufacturers include more powerful data processors and more memory therein. Moreover, such apparatus has for some time now attained a sufficient degree of sophistication that software applications can be downloaded thereto for performing special functions which can be optionally executed in response to users' commands. For example, some smartphones now include text editor application software to assist with in writing documents, emails, blogs and social media content.
In order to provide digital apparatus, such as smartphone products, which are desirable to contemporary users, manufacturers of such products have sought to produce progressively more compact digital apparatus. A consequence of such miniaturization is that the aforementioned touch screen keyboard 30 has evolved by one or more of: including more user accessible keys, employing keys of smaller physical size, employing multifunction keys. Moreover, a further consequence of such miniaturization is that the aforementioned display screen 20 is of increased pixel resolution for presenting finer detail. Such evolution of the keyboard 30 and the display 20 results in problems for users with diminished eyesight and lack of finger nimbleness experiencing difficulty when working with contemporary digital apparatus such as smartphones. In order to address such problems, it is contemporary practice to provide users with a pointed stylus for pressing miniature keys and also with optical magnifies, for example magnifying lenses for observing miniature displays. Moreover, multifunction keys are susceptible to reducing a total number of keys require but renders user data entry laborious unless users have superlative finger nimbleness. A solution to these problems that exist today is to have separate wireless external keyboards as discussed below.
As mentioned, digital apparatus is able to communicate with devices in the near proximity using NFC or similar wireless protocols. The NFC technology is based on a combination of contactless identification technology akin to RFID and various connection technologies. Standards have become established which define how devices employing such technologies can inter-operate to form peer-to-peer (P2P) networks. NFC operates in a frequency range in an order of 13.56 MHz over a distance of typically a few centimeters. Moreover, efforts have been hitherto applied to standardize NFC-technology; such standards include ISO 18092, ISO 21481, ECMA (340, 352 and 356) and ETSI TS 102 190. Furthermore, such NFC-technology is also compatible with contactless infrastructure for smartcards based on a standard ISO 14443 A, including Philips' MIFARE-technology and Sony's FeliCa-card.
Typically e.g. a mobile phone may set up an intermittent continuous NFC field in a state that we may call sniffer mode. In sniffer mode, the average current needed for this from the mobile phone is rather small, typically in the area of one mA. The sniffer mode is typically a repetitive short duration pulse train that is repeated at intervals of a few hundred milliseconds. The pulses typically are too short for an accessory NFC device to harvest significant energy therefrom. An electromagnetic field then surrounds the mobile phone. When an accessory NFC device approaches the mobile phone acting as an active NFC device, the active NFC device detects that the impedance of its antenna changes and will start a procedure to investigate and connect the active and the accessory NFC devices. When the active NFC device detects such a change of impedance, the active NFC device will transmit longer pulses with sufficient energy for the accessory NFC device to start. The pulses also comprise an initialization sequence. Accordingly, an accessory NFC device will initiate communication with the active NFC device.
When the two NFC devices are connected, data exchange mode is enabled. In data exchange mode, a short chunk of information is transferred one or both ways, the exchange mode is terminated, and sniffer mode is reinstated.
One example in the art that present harvesting of power from a second NFC device to a first NFC device is the Patent publication US 20140170976 A1 of Broadcom Corporation. This application uses the existing NFC technology as specified in the current standards.
Other remote wireless keyboards are known. For example, in a published U.S. Pat. No. 6,133,833, there is described a wireless keyboard or keypad which is powered remotely by a radio frequency exciter/receiver. The wireless keyboard is adapted for use in a radio frequency identification system. Moreover, the wireless keyboard and the exciter/receiver communicate without wires via electrostatic or electromagnetic radiation. No power source is integrated with the wireless keypad. It is alleged that the wireless keypad is readily added to, or retrofitted into, an existing radio frequency identification system. The keyboard has a plurality of keys or control members that are manually actuated. Depression of a key or button causes a predetermined response signal associated with that key or button to be generated. The response signal relates to an operation for a device or system associated with the exciter/receiver. Implementation of the wireless keyboard involves coupling an antenna comprising an inductor and a capacitor directly to an array of RFID devices which are selectively connected to the antenna in response to keys or buttons being user-actuated.
A wireless keyboard as described in the foregoing is of relatively larger physical size in comparison to a smartphone. The keyboard is bulky, not a mobile solution and is not mechanical designed to fit together with different types of digital apparatus. Moreover, such a keyboard is often implemented such that a smartphone could not be capable of coupling sufficiently well to provide power to the keyboard.
The PCT application WO 2007/089158 A1 with the title “External Keyboard” presents a keyboard including user-operable alpha-numeric keys. One or more identification devices associated with the user-operable keys are included in the keyboard. When placed in proximity to the keyboard, the one or more identification devices selectively communicate with a digital apparatus in response to user-actuation of the user-operable keys. The keyboard comprises a flexible substrate for enabling the keyboard to be folded into a non-deployed inactive state, and unfolded into a deployed active state for communicating with the digital apparatus. When the keyboard is in near proximity to the digital apparatus, the keyboard communicates with the digital apparatus by way of near-field magnetic and/or electrostatic coupling. The keyboard includes an intermediate resonant circuit for interfacing between the one or more identification devices and the digital apparatus; the resonant circuit includes a component spatially disposed to overlay a first region onto the digital apparatus in use, and to overlay a second region coupled to the one or more identification devices in use for coupling signals there between. The keyboard is especially useful for digital apparatus for rendering data entry easier.
The external keyboard as described in the foregoing is not optimized for integrating the keyboard to all kinds of digital apparatus in a seamless way. In this solution, the external keyboard and the digital apparatus are operating as two separate units. Consequently, the external keyboard does not share common functionality with the digital apparatus, wherein the two units can interoperate for enhancing the usability. Moreover, the mentioned keyboard is missing a versatile cover solution that implements mechanical design with the user interface functionality and at the same time protects the digital apparatus.